Methods for integrated microstrip and substrate integrated waveguide circulators/isolators formed with co-fired magnetic-dielectric composites

ABSTRACT

Disclosed are embodiments of microstrip and substrate integrated waveguide circulators/isolators which can be integrated with a substrate. This composite structure can serve as a platform for other components, allowing for improved miniaturization of components. Embodiments of the disclosure can be particular advantageous in the high frequency ranges, such as above 1.8GHz or above 3GHz, which allows devices to be used in the 5G space.

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

This Application is a divisional of U.S. application Ser. No.15/807,914, filed Nov. 9, 2017, titled “INTEGRATED MICROSTRIP ANDSUBSTRATE INTEGRATED WAVEGUIDE CIRCULATORS/ISOLATORS FORMED WITHCO-FIRED MAGNETIC-DIELECTRIC COMPOSITES,” which claims the benefit ofU.S. Provisional Application No. 62/421,786, filed Nov. 14, 2016, titled“INTEGRATED MICROSTRIP CIRCULATORS FORMED WITH CO-FIREDMAGNETIC-DIELECTRIC COMPOSITES,” U.S. Provisional Application No.62/506,958, filed May 16, 2017, titled “INTEGRATED MICROSTRIPCIRCULATORS FORMED WITH CO-FIRED MAGNETIC-DIELECTRIC COMPOSITES” and theentirety of each of which is incorporated herein by reference.

BACKGROUND Field

Embodiments of the disclosure relate to co-fired microstrip circulatorsand/or substrate integrated waveguide circulators useful for 5G systems,for example operating at frequencies of 1.8 GHz and above.

Description of the Related Art

Circulators and isolators are passive electronic devices that are usedin high-frequency (e.g., microwave) radio frequency systems to permit asignal to pass in one direction while providing high isolation toreflected energy in the reverse direction. Circulators and isolatorscommonly include a disc-shaped assembly comprising a disc-shaped ferriteor other ferromagnetic ceramic element, disposed concentrically withinan annular dielectric element. Ferrite materials (spinel, hexagonal orgarnet) have suitable low-loss microwave characteristics. The annulardielectric element is similarly commonly made of ceramic material.

SUMMARY

Disclosed herein are embodiments of an integrated microstrip circulator,the circulator comprising a dielectric substrate having an aperture, anda magnetic oxide disc fit within the aperture in the substrate, thedielectric substrate and magnetic oxide disc being co-fired together tocontain the magnetic oxide disc within the aperture of the dielectricsubstrate.

In some embodiments, the circulator can further comprise a thin filmcircuit. In some embodiments, the magnetic oxide disc can be a yttriumiron garnet disc. In some embodiments, the circulator can be configuredfor use in above 3 MHz systems. In some embodiments, the disc can bemagnetized prior to insertion within the aperture. In some embodiments,the circulator can further comprise a coupler, switch, and load locatedon the dielectric substrate. In some embodiments, the integratedmicrostrip circulator can be shaped like a square tile.

Also disclosed herein are embodiments of a method of forming a co-firedintegrated microstrip circulator, the method comprising preparing aferrite disc, preparing a dielectric substrate, the dielectric substratehaving an aperture, translating the ferrite disc into the aperture inthe dielectric substrate to form a composite structure, and co-firingthe composite structure to shrink the dielectric substrate round theferrite disc.

In some embodiments, the ferrite disc can be a magnetic oxide disc. Insome embodiments, the dielectric substrate can be generally square orrectangular shaped. In some embodiments, the method can further compriseadding additional radiofrequency components onto the substrate. In someembodiments, the method can further comprise slicing the compositestructure to a particular thickness, wherein each slice contains both aportion of the ferrite disc and a portion of the dielectric substrate.In some embodiments, the method can further comprise contacting amagnetic disc onto the composite structure to form a microstripcirculator. In some embodiments, the ferrite disc can be magnetizedprior to translating. In some embodiments, the method can furthercomprise applying a coupler, switch, and load to the dielectricsubstrate.

Also disclosed herein are embodiments of a radiofrequency antennasystem, the system comprising a dielectric substrate having an aperture,a magnetic oxide disc fit within the aperture in the substrate, thedielectric substrate and magnetic oxide disc being co-fired together tocontain the magnetic oxide disc within the aperture of the dielectricsubstrate, a transmit power amplifier, a receive low noise amplifier,and a filter.

In some embodiments, the system can further comprise a semiconductoramplifier. In some embodiments, the system can further comprise acoupler, switch, and load located on the dielectric substrate. In someembodiments, the system can be configured to operate as a 5G system. Insome embodiments, the disc can be magnetized prior to insertion withinthe aperture.

Disclosed herein are embodiments of an integrated microstrip orsubstrate integrated waveguide circulator comprising a dielectricsubstrate having an aperture, and a ferrite disc fit within the aperturein the substrate, the dielectric substrate and ferrite disc beingco-fired together to contain the ferrite disc within the aperture of thedielectric substrate.

In some embodiments, the circulator can further comprise a thin filmcircuit. In some embodiments, the ferrite disc can be a yttrium irongarnet disc. In some embodiments, the circulator can be configured foruse in above approximately 1.8 GHz systems. In some embodiments, thecirculator can further include a coupler, switch, and load located onthe dielectric substrate. In some embodiments, no adhesive may be used.In some embodiments, the dielectric substrate and ferrite disc can beco-fired at a temperature of at least 1000° C. In some embodiments, theferrite disc and the dielectric substrate can be metallized together.

Also disclosed herein are embodiments of a method of forming a co-firedintegrated microstrip or substrate integrated waveguide circulator, themethod comprising preparing a ferrite disc, preparing a dielectricsubstrate, the dielectric substrate having an aperture, translating theferrite disc into the aperture in the dielectric substrate to form acomposite structure, co-firing the composite structure to shrink thedielectric substrate round the ferrite disc, and metallizing thecomposite structure.

In some embodiments, the ferrite disc can be a yttrium iron garnet disc.In some embodiments, the co-firing can be at a temperature of at least1000° C. In some embodiments, the method can further include addingadditional radio frequency components onto the substrate. In someembodiments, no adhesive may be used.

In some embodiments, the method can further include slicing thecomposite structure to a particular thickness, wherein each slicecontains both a portion of the ferrite disc and a portion of thedielectric substrate. In some embodiments, the method can furtherinclude contacting a magnetic disc onto the composite structure to forma microstrip or substrate integrated waveguide circulator. In someembodiments, the method can further include applying a coupler, switch,and load to the dielectric substrate.

Also disclosed herein are embodiments of a radio frequency antennasystem comprising a dielectric substrate having an aperture, a ferritedisc fit within the aperture in the dielectric substrate, the dielectricsubstrate and ferrite disc being co-fired together to contain theferrite disc within the aperture of the dielectric substrate, a transmitpower amplifier, a receive low noise amplifier, and a filter.

In some embodiments, the system can further include a semiconductoramplifier. In some embodiments, the system can further include acoupler, switch, and load located on the dielectric substrate. In someembodiments, the system can be configured to operate as a 5G system. Insome embodiments, no adhesive may be used.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 schematically shows how materials having one or more featuresdescribed herein can be designed, fabricated, and used.

FIG. 2 illustrates a magnetic field v. loss chart.

FIG. 3 illustrates an embodiment of a composite structure having aferrite cylinder within a rectangular prism dielectric substrate.

FIG. 4 illustrates an embodiment of a composite tile.

FIG. 5 illustrates an integrated microstrip circulator without a magnet.

FIG. 6 illustrates an integrated microstrip circulator with a magnet.

FIG. 7 is a schematic diagram of one example of a communication network.

FIG. 8 is a schematic diagram of one example of a communication linkusing carrier aggregation.

FIG. 9A is a schematic diagram of one example of a downlink channelusing multi-input and multi-output (MIMO) communications.

FIG. 9B is schematic diagram of one example of an uplink channel usingMIMO communications.

FIG. 10 illustrates a schematic of an antenna system.

FIG. 11 illustrates a schematic of an antenna system with an embodimentof an integrated microstrip circulator.

FIG. 12 illustrates a MIMO system incorporating embodiments of thedisclosure.

FIG. 13 is a schematic diagram of one example of a mobile device.

FIG. 14 is a schematic diagram of a power amplifier system according toone embodiment.

FIG. 15 illustrates a method of forming a composite integratedmicrostrip circulator.

FIG. 16 illustrates an embodiment of an integrated microstrip circulatorfor testing.

FIGS. 17A-20B illustrate testing results of an embodiment of thedisclosed integrated microstrip circulator of FIG. 16.

FIG. 21 illustrates an embodiment of a substrate integrated waveguide(SIW) incorporating embodiments of the disclosure.

FIG. 22 illustrates an embodiment of a substrate integrated waveguide(SIW) circulator.

DETAILED DESCRIPTION

Disclosed herein are embodiments of integrated architectures for use inradiofrequency (RF) and/or electronic environments. The integratedarchitectures can include microstrip circulators, such as integratedceramic substrate microstrip circulators, that can be formed using aco-firing process with a dielectric tile substrate. Specifically, aferrite disc can be embedded into a dielectric substrate and co-fired toform an integrated microstrip circulator which may then serve as aplatform for other components, such as circuitry. Thus, adhesives andother connecting features can be avoided, allowing for easier productionand metallization of the microstrip circulators. Further, substrateintegrated waveguide (SIWs) circulators can also be formed using theco-firing process disclosed herein. In some embodiments, a stripline(tri-plate) circulator can be formed as well using embodiments discussedherein.

Embodiments of the disclosure could advantageously allow for 5G systems,in particular operating at 1.8 GHz and above (and in some embodiment 3GHz and above), to form integrated architectures which can includedifferent components, such as antennas, circulators, amplifiers, and/orsemiconductor based amplifiers. By allowing for the integration of thesecomponents onto a single substrate, this can improve the overallminiaturization of the device. In some embodiments, the discloseddevices can be operable at frequencies between about 1.8 GHz and about30 GHz. In some embodiments, the disclosed device can be operable atfrequencies of greater than about 1, 2, 3, 4, 5, 10, 15, 20, or 25 GHz.In some embodiments, the disclosed device can be operable at frequenciesof less than 30, 25, 20, 15, 10, 5, 4, 3, or 2 GHz.

In some embodiments, the integrated architecture can include adirectional coupler and/or isolator in a package size which is not muchlarger than a standard isolator, or equivalent size to a standardisolator. In some embodiments, the integrated architecture can include ahigh power switch. In addition to using the dielectric tile as thesubstrate for the impedance transformer, it could also be used as thesubstrate for the coupler, switch and termination.

FIG. 1 schematically shows how one or more chemical elements (block 1),chemical compounds (block 2), chemical substances (block 3) and/orchemical mixtures (block 4) can be processed to yield one or morematerials (block 5) having one or more features described herein. Insome embodiments, such materials can be formed into ceramic materials(block 6) configured to include a desirable dielectric property (block7), a magnetic property (block 8).

In some embodiments, a material having one or more of the foregoingproperties can be implemented in applications (block 10) such asradio-frequency (RF) application. Such applications can includeimplementations of one or more features as described herein in devices12. In some applications, such devices can further be implemented inproducts 11. Examples of such devices and/or products are describedherein.

Microstrip Circulators/Isolators

Circulators are passive multiport devices which can receive and transmitdifferent signals, such as microwave or radiofrequency (RF). These portscan be an external waveguide or transmission line which connects to andfrom the circulator. Isolators are similar to circulators, but one ormore of the ports can be terminated. Hence, circulator and isolator canbe used interchangeably herein as they can be similar in generalstructural. Thus, all discussion below can apply both to circulators andisolators. Further, the circulators and isolators can be known ascirculator packages and isolator packages, for example if they includeextra components discussed herein.

Circulators generally can operate in either of the above or belowresonance operating regions. This is shown in FIG. 2. In someembodiments, above-resonance frequencies can be advantageous for narrowband, sub 4 GHz circulators. For higher frequencies, the below resonanceregion can be more advantageous.

Previously, some all-ferrite microstrip circulators have been used, inparticular for radar T/R modules. Circuitry can be printed onto theall-ferrite microstrip circulator and a magnet can be added on top todirect the signal. For example, a metallization pattern is formed onto aferrite substrate. Typically, the metallization pattern consists of acentral disc and multiple transmission lines.

Microstrip circulators in particular typically work in the belowresonance operating region. They use a very small magnet or can beself-biased, such as in the case of hexagonal ferrites. However, squaretiles can be a difficult shape to magnetize uniformly, in particular forthe all-ferrite microstrip circulators known in the art. Thus, they willoperate close to the low field loss region. When transformers aremounted on the lossy unmagnetized ferrite, performance suffers. Further,increased power will make the poor performance even more known. Thus,circulators known in the art suffer from issues due to the ferrite tilebeing poorly magnetized, leading to poor insertion loss andintermodulation distortion (IMD), and degraded power performance.

Additionally, microstrip transmission lines suffer from increasingproblems with higher frequencies, such as “overmoding”. To avoid“overmoding”, that is the creation of unwanted modes in the microstripline, it can be advantageous to use thinner substrates and lowerdielectric constants at higher frequencies, such as disclosed below.However, this, in turn, can lead to radiation from open microstrip withconsequent losses and unwanted “box” modes in a transceiver enclosure.

Co-Fired Microstrip Circulators/Isolators and Substrate IntegratedWaveguide (SIW) Circulators/Isolators

Embodiments of the disclosure can improve overall magnetization andreduce performance issues that can occur for currently knowncirculators/isolators, in particular microstrip circulators/isolatorsand SIW circulators/isolators. Generally, the microstripcirculators/isolators and SIW circulators/isolators can be formed byembedding a ferrite disc, such as an oxide ferrite disc, or such as adisc made of yttrium iron garnet (YIG), directly into a dielectricsubstrate (for example in a hole/aperture), such as a high dielectricsubstrate. Unlike previously known methodologies, during the ceramicformation process, the combination of ferrite disc and dielectricsubstrate can then be fired together (e.g., co-fired) at hightemperatures to form a more solid composite structure. For example, theferrite disc and dielectric substrate can be co-fired together atgenerally the same or the same temperature. The co-fired assembly canthen be metallized, thus providing the base for microstripcirculators/isolators and SIW circulators/isolators.

Advantageously, the co-firing of the dielectric substrate and ferritedisc can be performed without negatively impacting, or withoutsignificantly negatively impacting, the properties of either the ferritedisc or the dielectric substrate. Thus, in some embodiments the disc andsubstrate can be fired at the same time. Specifically, they can be firedat the same time while or after the ferrite disc is inserted into thedielectric substrate.

Specifically, the combination of the ferrite disc within thehole/aperture of the dielectric substrate can be co-fired so that thedielectric substrate shrinks around the ferrite disc. Both of thesematerials can be “fireable”, meaning they have the ability to be firedor sintered in an oven/kiln/other heating device. In some embodiments,firing can change one or more properties of the material, such as theceramic materials discussed herein. Embodiments of these assemblies canbe used as microstrip circulators/isolators and SIWcirculators/isolators for radiofrequency applications, such as for 5Gapplications.

Without the co-firing process, circuit metallization would not be ableto be applied as the firing process can destroy the metallization, whichis a significant problem for circulators/isolators known in the art thatrequire separate firing of the dielectric substrate and ferrite disc.Methods previously used to avoid this issue are the use of all-ferritecirculators/isolators, though these have significant drawbacks asdiscuss above. Thus, embodiments of the disclosure alleviate many of theissues known in the art by allowing the dielectric substrate and ferritedisc to be co-fired together.

In some embodiments, the dielectric substrate and ferrite disc can beco-fired at temperatures of above 700, 800, 900, 1000, 1100, 1200, 1300,1400, 1500, or 1600° C. In some embodiments, the dielectric substrateand ferrite disc can be co-fired at temperatures of below 700, 800, 900,1000, 1100, 1200, 1300, 1400, 1500, or 1600° C.

Table I illustrates examples of ferrites and compatible dielectric thatcan be co-fired together. In some embodiments, the ferrite disc and thedielectric substrate are two different materials.

TABLE 1 Co-Fireable Materials Compatible With Ferrites Ferrite FiringCompatible Co-Fired Compatible Co-Fired Compatible Co-Fired BasicFerrite Range/Maximum Dielectric With Dielectric With Dielectric WithMaterial Dielectric Co-Fire Dielectric Constant Dielectric ConstantDielectric Constant System Temperature Range 4-10 Range 10-40 Range40-100+ YFe, YAlFe, 1300-1500° C. N/A Mg—Ca—Al—Zn Bi Pyrochlores; Li,Na, Bi GdYFe/CaVFe Titanates Vanadate/Molybdate/Tungstate Garnets basedScheelites NiZn Spinels 1300° C. BaWO4+ Additives; Mg—Ca—Al—Zn N/A MgSpinels Na, Li Molybdate Titanates Spinels BiY Garnets 800-1000° C. N/ALi, Bi Bi Pyrochlores; Li, Na, Bi Li Spinels Molybdate/Tungstate;Vanadate/Molybdate based Bi, Cu doped Na, Li, Ca, Mg, Zn ScheelitesSpinels Vanadate Garnets

While Table 1 illustrates a number of compatible co-fireable dielectricand ferrite materials, it will be understood that the disclosure is notso limited to the above materials, and that other compatible co-firingmaterials can be used as well. For example, garnets, spinels, ferrites,oxides, molybdates, tungstates, titanates, vanadates, and pyrocholorescan all be used.

Additional circuitry, connections, etc., such as formed from silver orother metalized substances, can be added to a co-fired assembly for themicrostrip circulators/isolators and SIW circulators/isolators.

Previous circulators/isolators require the use glue (epoxy, or otheradhesives) which would be destroyed by the metallization processtemperature, such as taught in U.S. Pat. No. 7,687,014, herebyincorporated by reference in its entirety. Thus, previously there weresignificant difficulties in preparing metalized circulators/isolators asthis process would loosen the combination of the ferrite disc anddielectric substrate. In fact, without the disclosed co-firing process,it is extremely difficult, if not impossible, to metallize the assemblyonce there is adhesive. This is because the temperature required formetallization is much higher than the use temperature for the adhesive,causing the adhesive to melt and/or lose adhesive. Further, the glue islossy, increasing the insertion loss of glued components. The dielectricloss of the glue at high frequencies is greater than the magnetic or thedielectric material

Moreover, previous iterations of assemblies fire the fireable substrateseparate from the fireable disc due to the temperature for firing thesubstrate being too high, which can lead to melting, or at leastconsiderably damaging the properties of the internal ferrite disc.Either both segments can be fired separately, or the ring can be firedfirst and then the assembly is fired together. For each of theseapproaches, the substrate will not sufficiently shrink around the discand thus an adhesive will be needed to keep assembly together, leadingto the issues discussed above.

Accordingly, embodiments of the disclosure do not use glue, epoxy, orother adhesives to combine the ferrite and the dielectric together,providing for advantageous metallization over the known art, and thuscan be considered a “glueless assembly”. Instead, in some embodimentsthe co-firing of the dielectric substrate and the ferrite disc cancreate mechanical friction between the disc and substrate, such asexpanding of the disc and/or shrinking of the substrate, to hold the twocomponents together.

Any number of different disc materials can be used, such as ferritematerials discussed above in Table 1. In some embodiments, thesaturation magnetization levels of the ferrite disc material can rangebetween 1000-5000 (or about 1000-about 5000) gauss. In some embodiments,the saturation magnetization levels of the ferrite disc material canrange between 4000-5000 (or about 4000-about 5000) gauss. In someembodiments, the saturation magnetization levels of the ferrite discmaterial can be 1000, 2000, 3000, 4000, or 5000 gauss. In someembodiments, the saturation magnetization levels of the ferrite discmaterial can be greater than 1000, 2000, 3000, 4000, or 5000 gauss. Insome embodiments, the saturation magnetization levels of the ferritedisc material can be less than 1000, 2000, 3000, 4000, or 5000 gauss. Insome embodiments, the ferrite disc can be a magnetic oxide. In someembodiments, the ferrite disc can be a yttrium iron garnet.

Further, any number of different dielectric substrates known in the artcan be used (See Table 1). In some embodiments, the dielectric can beformed from dielectric powder or low temperature co-fired ceramic (LTCC)tape. In some embodiments, the dielectric constant of the dielectricsubstrate can be below approximately 4 and above 6, 10, 15, 20, 25, 30,40, 50, 60, 100, or 150. In some embodiments, the dielectric constant ofthe dielectric substrate can range from 6-30 (or about 6 to about 30).In some embodiments, the dielectric constant of the dielectric substratecan be below about 150, 100, 60, 50, 40, 30, 25, 20, 15, or 10. In someembodiments, the dielectric constant of the dielectric substrate canrange from 10-40 (or about 10 to about 40). In some embodiments, thedielectric constant of the dielectric substrate can range from 4-10 (orabout 4 to about 10). In some embodiments, the dielectric constant ofthe dielectric substrate can range from 40-100 (or about 40 to about100).

Co-Fired Assemblies for Microstrip Circulators/Isolators and SIWCirculators/Isolators

In particular, to form the co-fired circulator/isolator 100, a ferritedisc 102, or other magnetic disc, can be inserted into an aperture of adielectric substrate 104 as shown in FIG. 3. This can be done for bothmicrostrip and SIW circulators/isolators, though FIG. 3 shows amicrostrip circulator/isolator. In some embodiments, the disc 102 can bea cylindrical rod, though the particular shape is not limiting. The disc102 can be green, previously fired, or not-previously fired.

Further, the substrate 104 can generally be a rectangular shape asshown, but other shapes can be used as well. Once the disc 102 is insidethe substrate 104, the components can be co-fired together, using such amethod as discussed in U.S. Pat. No. 7,687,014, but without using anadhesive. This co-firing process, further discussed herein, can causethe substrate 104 to shrink around the disc 102 and hold it in place toform the composite structure 100. This composite structure 100 can thenbe sliced to form the chip structure as shown in FIG. 4 or FIG. 22.However, in some embodiments, slicing is not performed and thecomponents are co-fired together at their final thickness. In someembodiments, a plurality of different discs can be inserted into asingle substrate in a plurality of different apertures.

Thus, in some embodiments a ferrite disc can be co-fired into a squareor rectangular dielectric substrate, or any other shaped substrate,which can then serve as a platform for other components, such ascircuitry, magnets, switches, couplers, amplifiers, etc. This compositestructure can then be magnetized to serve as a microstrip or SIWcirculator and/or isolator package, for example, or the ferrite disccould have been magnetized prior to insertion. In some embodiments, theferrite disc can be magnetized prior to the co-firing step.

Thus, using a co-firing process, a ferrite disc 102 can be embedded intoa dielectric tile 104 to form an assembly 100, as shown in FIG. 4. Thethin ferrite disc shown in the figure can be significantly easier tomagnetize uniformly than a square, or other oddly shaped piece, known inthe art. In some embodiments, the dielectric tile could be about 25 mmsquare though the particular dimensions are not limiting. This can beused in the 3-4 (or about 3-about 4) GHz region, but the frequency isnot limiting.

Using the dielectric tile assembly 100, a transformer 200 can then beproduced as shown in FIG. 5. As shown, the substrate 104 has space leftover for other component attachments. After forming the transformer 200,only a small magnet needs to be placed on the tile, as shown in FIG. 6.Thus, assembly is much less complex than previously done. Thetransformer length depends on frequency and dielectric constant of thesubstrate.

In addition to using the dielectric tile 104 as the substrate for theimpedance transformer, it could also be used as the substrate for thecoupler, switch, and termination. Thus, a number of other components canbe added onto the substrate after co-firing, reducing the overallfootprint of the device. Further, circuit metallization could be added,but only after the device has been co-fired as discussed above.Microstrip isolators/circulators can be used as interstage isolators inthe amplifier chain, as switched circulators as part of TDD designs oras circulators in FDD designs.

As mentioned above, in some embodiments the co-firing process can beused to form waveguide circulators/isolators, such as substrateintegrated waveguide (SIW) circulators/isolators, essentially dielectricfilled waveguides bounded by metallization that cannot readily radiate.These can be formed in bulk ceramic formed by complete thick filmmetallization. Thus, for example, a co-fired structure of magnetic anddielectric material can be used to form a SIW circulator at ˜24 GHz.

FIG. 21 illustrates an embodiment of a substrate integrated waveguide1000. As shown, the SIW 1000 can include a first port 1002 and a secondport 1004. Between the two ports 1002/1004 can be a top ground plate1006 and a bottom ground plate 1012 which sandwich a dielectricsubstrate 1008. The SIW 1000 can further include a plurality of metalvias 1010 extending through the thickness of the dielectric substrate1008.

In some embodiments, the SIW 1000 can be used as a circulator or anisolator, similar to what is described above. An example of a three portcirculator/isolator is shown in FIG. 22, though other constructions of aSIW circulator/isolator can be used as well and the particular design isnot limiting. As shown, the dielectric substrate 1008 can include ahole, aperture, etc., which can receive a ferrite disc/rod 1020. Asdiscussed herein, the ferrite disc 1020 can be co-fired within thedielectric substrate 1008, and metallization can be performed after theco-firing. The circulator/isolator shown in FIG. 22 can be incorporatedinto a transformer such as shown in FIGS. 5-6.

Previews SIWs use PCB laminate material is used to form the broad wallsof the waveguide, and closely spaced vias form the narrow walls, whichcan create a rectangular waveguide filled with printed circuit board(PCB) laminate material. An alternative to the use of PCB is a lowtemperature co-fired ceramic (LTCC), where a fireable ceramic tapereplaces the PCB material. LTCC is limited in thickness and does notallow easy insertion of other dielectric or magnetic ceramics in tape orbulk form, because of firing temperature and/or expansion constraints.However, embodiments of the disclosed co-fired ceramics can replace thePCB and LTCC. Thus, embodiments of the disclosure can be used to createwaveguides in bulk ceramic form by complete thick film metallization.

Once the composite structure is formed, other components can be addedonto the substrate. For example, some components are printed on thedielectric part of the substrate, for example a coupler or microstripfilter. Antennas, amplifiers (e.g., semiconductor based amplifiers), canbe integrated onto the assembly as well. Others may be mounted inpackaged form onto the substrate, for example a packaged BAW or SAWfilter or packaged amplifier.

Thus, embodiments of the disclosure can form an integrated solutionwhich can include a directional coupler and/or isolator in a packagesize which is comparable to a standard isolator, depending on the typeof component. In some embodiments, the disclosed circulator will be nolarger (and depending on the ferrite/dielectric combination chosen couldbe smaller) than all current ferrite microstrip circulators. In someembodiments, the disclosed assembly can be 100%, 95%, 90%, 85%, or 80%of the dimensions as compared to a typical assembly which does not useco-firing process. In some embodiments, the disclosed assembly can beless than 100%, 95%, 90%, 85%, or 80% of the dimensions as compared to atypical assembly which does not use co-firing process. In someembodiments, the disclosed assembly can be greater than 95%, 90%, 85%,or 80% of the dimensions as compared to a typical assembly which doesnot use co-firing process.

5G Applications

Embodiments of the disclosed co-fired composite microstripcirculators/isolators and SIW circulators/isolators can be particularlyadvantageous for 5^(th) generation wireless system (5G) applications,though could also be used for early 4G and 3G applications as well. 5Gtechnology is also referred to herein as 5G New Radio (NR). 5G networkscan provide for significantly higher capacities than current 4G system,which allows for a larger number of consumers in an area. This canfurther improve uploading/downloading limits and requirements. Inparticular, the large number of microstrip circulators/isolators and SIWcirculators/isolators, such as those described herein, needed for 5G(typically 1 per front end module or FEM) requires further integrationof components. The disclosed embodiments of microstripcirculators/isolators and SIW circulators/isolators can allow for thisintegration and thus can be particularly advantageous. Other componentsin the front end module will be microstrip or SMT based.

Preliminary specifications for 5G NR support a variety of features, suchas communications over millimeter wave spectrum, beam formingcapability, high spectral efficiency waveforms, low latencycommunications, multiple radio numerology, and/or non-orthogonalmultiple access (NOMA). Although such RF functionalities offerflexibility to networks and enhance user data rates, supporting suchfeatures can pose a number of technical challenges.

The teachings herein are applicable to a wide variety of communicationsystems, including, but not limited to, communication systems usingadvanced cellular technologies, such as LTE-Advanced, LTE-Advanced Pro,and/or 5G NR.

FIG. 7 is a schematic diagram of one example of a communication network10. The communication network 10 includes a macro cell base station 1, amobile device 2, a small cell base station 3, and a stationary wirelessdevice 4.

The illustrated communication network 10 of FIG. 7 supportscommunications using a variety of technologies, including, for example,4G LTE, 5G NR, and wireless local area network (WLAN), such as Wi-Fi.Although various examples of supported communication technologies areshown, the communication network 10 can be adapted to support a widevariety of communication technologies.

Various communication links of the communication network 10 have beendepicted in FIG. 7. The communication links can be duplexed in a widevariety of ways, including, for example, using frequency-divisionduplexing (FDD) and/or time-division duplexing (TDD). FDD is a type ofradio frequency communications that uses different frequencies fortransmitting and receiving signals. FDD can provide a number ofadvantages, such as high data rates and low latency. In contrast, TDD isa type of radio frequency communications that uses about the samefrequency for transmitting and receiving signals, and in which transmitand receive communications are switched in time. TDD can provide anumber of advantages, such as efficient use of spectrum and variableallocation of throughput between transmit and receive directions.

As shown in FIG. 7, the mobile device 2 communicates with the macro cellbase station 1 over a communication link that uses a combination of 4GLTE and 5G NR technologies. The mobile device 2 also communicates withthe small cell base station 3 which can include embodiments of thedisclosure. In the illustrated example, the mobile device 2 and smallcell base station 3 communicate over a communication link that uses 5GNR, 4G LTE, and Wi-Fi technologies.

In certain implementations, the mobile device 2 communicates with themacro cell base station 2 and the small cell base station 3 using 5G NRtechnology over one or more frequency bands that are less than 6Gigahertz (GHz). In one embodiment, the mobile device 2 supports a HPUEpower class specification.

The illustrated small cell base station 3, incorporating embodiments ofthe disclosure, also communicates with a stationary wireless device 4.The small cell base station 3 can be used, for example, to providebroadband service using 5G NR technology over one or more frequencybands above 6 GHz, including, for example, millimeter wave bands in thefrequency range of 30 GHz to 300 GHz.

In certain implementations, the small cell base station 3 communicateswith the stationary wireless device 4 using beamforming. For example,beamforming can be used to focus signal strength to overcome pathlosses, such as high loss associated with communicating over millimeterwave frequencies.

The communication network 10 of FIG. 7 includes the macro cell basestation 1, which can include embodiments of the disclosure (such as themicrostrip circulators/isolators and SIW circulators/isolators), and thesmall cell base station 3. In certain implementations, the small cellbase station 3 can operate with relatively lower power, shorter range,and/or with fewer concurrent users relative to the macro cell basestation 1. The small cell base station 3 can also be referred to as afemtocell, a picocell, or a microcell.

Although the communication network 10 is illustrated as including twobase stations, the communication network 10 can be implemented toinclude more or fewer base stations and/or base stations of other types.

The communication network 10 of FIG. 7 is illustrated as including onemobile device and one stationary wireless device. The mobile device 2and the stationary wireless device 4 illustrate two examples of userdevices or user equipment (UE). Although the communication network 10 isillustrated as including two user devices, the communication network 10can be used to communicate with more or fewer user devices and/or userdevices of other types. For example, user devices can include mobilephones, tablets, laptops, IoT devices, wearable electronics, and/or awide variety of other communications devices.

User devices of the communication network 10 can share available networkresources (for instance, available frequency spectrum) in a wide varietyof ways.

Enhanced mobile broadband (eMBB) refers to technology for growing systemcapacity of LTE networks. For example, eMBB can refer to communicationswith a peak data rate of at least 10 Gbps and a minimum of 100 Mbps foreach user device. Ultra-reliable low latency communications (uRLLC)refers to technology for communication with very low latency, forinstance, less than 2 ms. uRLLC can be used for mission-criticalcommunications such as for autonomous driving and/or remote surgeryapplications. Massive machine-type communications (mMTC) refers to lowcost and low data rate communications associated with wirelessconnections to everyday objects, such as those associated with Internetof Things (IoT) applications.

The communication network 10 of FIG. 7 can be used to support a widevariety of advanced communication features, including, but not limitedto eMBB, uRLLC, and/or mMTC.

A peak data rate of a communication link (for instance, between a basestation and a user device) depends on a variety of factors. For example,peak data rate can be affected by channel bandwidth, modulation order, anumber of component carriers, and/or a number of antennas used forcommunications.

For instance, in certain implementations, a data rate of a communicationlink can be about equal to M*B*log₂(1+S/N), where M is the number ofcommunication channels, B is the channel bandwidth, and S/N is thesignal-to-noise ratio (SNR).

Accordingly, data rate of a communication link can be increased byincreasing the number of communication channels (for instance,transmitting and receiving using multiple antennas), using widerbandwidth (for instance, by aggregating carriers), and/or improving SNR(for instance, by increasing transmit power and/or improving receiversensitivity).

5G NR communication systems can employ a wide variety of techniques forenhancing data rate and/or communication performance.

FIG. 8 is a schematic diagram of one example of a communication linkusing carrier aggregation. Carrier aggregation can be used to widenbandwidth of the communication link by supporting communications overmultiple frequency carriers, thereby increasing user data rates andenhancing network capacity by utilizing fragmented spectrum allocations.

In the illustrated example, the communication link is provided between abase station 21 and a mobile device 22. As shown in FIG. 8 thecommunications link includes a downlink channel used for RFcommunications from the base station 21 to the mobile device 22, and anuplink channel used for RF communications from the mobile device 22 tothe base station 21.

Although FIG. 8 illustrates carrier aggregation in the context of FDDcommunications, carrier aggregation can also be used for TDDcommunications.

In certain implementations, a communication link can provideasymmetrical data rates for a downlink channel and an uplink channel.For example, a communication link can be used to support a relativelyhigh downlink data rate to enable high speed streaming of multimediacontent to a mobile device, while providing a relatively slower datarate for uploading data from the mobile device to the cloud.

In the illustrated example, the base station 21 and the mobile device 22communicate via carrier aggregation, which can be used to selectivelyincrease bandwidth of the communication link. Carrier aggregationincludes contiguous aggregation, in which contiguous carriers within thesame operating frequency band are aggregated. Carrier aggregation canalso be non-contiguous, and can include carriers separated in frequencywithin a common band or in different bands.

In the example shown in FIG. 8, the uplink channel includes threeaggregated component carriers f_(UL1), f_(UL2), and f_(UL3).Additionally, the downlink channel includes five aggregated componentcarriers f_(DL1), f_(DL2), f_(DL3), f_(DL4), and f_(DL5). Although oneexample of component carrier aggregation is shown, more or fewercarriers can be aggregated for uplink and/or downlink. Moreover, anumber of aggregated carriers can be varied over time to achieve desireduplink and downlink data rates.

For example, a number of aggregated carriers for uplink and/or downlinkcommunications with respect to a particular mobile device can changeover time. For example, the number of aggregated carriers can change asthe device moves through the communication network and/or as networkusage changes over time.

With reference to FIG. 8, the individual component carriers used incarrier aggregation can be of a variety of frequencies, including, forexample, frequency carriers in the same band or in multiple bands.Additionally, carrier aggregation is applicable to implementations inwhich the individual component carriers are of about the same bandwidthas well as to implementations in which the individual component carriershave different bandwidths.

FIG. 9A is a schematic diagram of one example of a downlink channelusing multi-input and multi-output (MIMO) communications. FIG. 9B isschematic diagram of one example of an uplink channel using MIMOcommunications.

MIMO communications use multiple antennas for simultaneouslycommunicating multiple data streams over common frequency spectrum. Incertain implementations, the data streams operate with differentreference signals to enhance data reception at the receiver. MIMOcommunications benefit from higher SNR, improved coding, and/or reducedsignal interference due to spatial multiplexing differences of the radioenvironment.

MIMO order refers to a number of separate data streams sent or received.For instance, MIMO order for downlink communications can be described bya number of transmit antennas of a base station and a number of receiveantennas for UE, such as a mobile device. For example, two-by-two (2×2)DL MIMO refers to MIMO downlink communications using two base stationantennas and two UE antennas. Additionally, four-by-four (4×4) DL MIMOrefers to MIMO downlink communications using four base station antennasand four UE antennas.

In the example shown in FIG. 9A, downlink MIMO communications areprovided by transmitting using M antennas 43 a, 43 b, 43 c, . . . 43 mof the base station 41 and receiving using N antennas 44 a, 44 b, 44 c,. . . 44 n of the mobile device 42. Accordingly, FIG. 9A illustrates anexample of M×N DL MIMO.

Likewise, MIMO order for uplink communications can be described by anumber of transmit antennas of UE, such as a mobile device, and a numberof receive antennas of a base station. For example, 2×2 UL MIMO refersto MIMO uplink communications using two UE antennas and two base stationantennas. Additionally, 4×4 UL MIMO refers to MIMO uplink communicationsusing four UE antennas and four base station antennas.

In the example shown in FIG. 9B, uplink MIMO communications are providedby transmitting using N antennas 44 a, 44 b, 44 c, . . . 44 n of themobile device 42 and receiving using M antennas 43 a, 43 b, 43 c, . . .43 m of the base station 41. Accordingly, FIG. 9B illustrates an exampleof N×M UL MIMO.

By increasing the level or order of MIMO, bandwidth of an uplink channeland/or a downlink channel can be increased.

Although illustrated in the context of FDD, MIMO communications are alsoapplicable communication links using TDD.

For these 5G networks, one form of base station will be massive multipleinput, multiple output (MIMO) based, with an array of perhaps 64-128antennas capable of multi-beam forming to interact with handheldterminals at very high data rates. Thus, embodiments of the disclosurecan be incorporated into the base stations to provide for high capacityapplications.

This approach is similar to radar phased array T/R modules, withindividual transceivers for each antenna element, although massive MIMOis not a phased array in the radar sense. The objective is optimumcoherent signal strength at the terminal(s) rather than directionfinding. Further, signal separation will be time division (TD) based,requiring a means of duplexing/switching to separate Tx and Rx signals

For discussion, it is assumed that there is one Tx, one Rx module, oneduplexing circulator and one antenna filter per antenna. However, otherconfigurations can be used as well.

FIG. 7 shows a simplified version of an RF transmission system, omittingdrivers and switching logic. As shown, the system can include a numberof different components, including microstrip circulators/isolators andSIW circulators/isolators. Thus, embodiments of the disclosure can beused as the microstrip circulators/isolators and SIWcirculators/isolators in the RF system, either for newly created systemsor as improved replacements for the previous systems.

FIG. 10 illustrates the integrated component of FIG. 4 discussed aboveonto the simplified RF antenna structure. As shown, the substrate caninclude the co-fired microstrip circulators/isolators and SIWcirculators/isolators disclosed herein. In addition, a coupler, switch,and load can also be applied to the dielectric tile outside of theferrite. The conductors and the ground plane could be in a thick filmsilver. In some embodiments, the circulator subassembly can also beintegrated with the power amplifier (PA) and loud noise amplifier (LNA)modules.

Embodiments of the disclosed microstrip circulators/isolators and SIWcirculators/isolators can have advantages over circulators and/or SIWsknown in the art. For example:

-   -   Couplers and other transmission lines have much lower insertion        loss compared with other couplers, such as semiconductor        couplers    -   Coupling is more consistent    -   Loads can dissipate heat more easily compared with soft        substrate    -   Circulators have lower loss than all-ferrite substrate based        devices    -   The dielectric is temperature stable, assisting the coupler and        circulator's performance    -   The size of the devices can be reduced by using higher        dielectric constant ceramic dielectric if required

Further, embodiments of the microstrip circulators/isolators and SIWcirculators/isolators can have the following advantages:

-   -   Heat/power dissipation/thermal conductivity for PA and load    -   Isotropic dielectric (except TTB) for coupler/filter design    -   Range of dielectric constant (4-100+) for size reduction    -   Low dielectric loss (coupler/filter)    -   Tight dielectric constant tolerance (coupler/filter/antenna)    -   Stable dielectric constant over temperature        (coupler/filter/circulator)    -   Modest Cost

On the other hand, soft substrate (e.g., softboards) can have thefollowing disadvantages:

-   -   Poor conductivity due to plastic conductivity    -   Anisotropic (xy versus z direction)    -   Only 3-10 with some, fixed with others    -   Higher losses    -   Looser tolerances    -   Unstable over temperature

Accordingly, embodiments of the disclosed microstripcirculators/isolators and SIW circulators/isolators can have significantadvantages over circulators and SIWs previously known in the art.

FIG. 12 illustrates another embodiment of a MIMO system that thedisclosed microstrip circulators/isolators and SIW circulators/isolatorscan be incorporated into. With the advent of massive MIMO for 5G systemthe current antennas will be replaced with antenna arrays with, forexample, 64 array elements. Each element can be fed by a separate frontend module (FEM) including the blocks shown in FIGS. 10 and 11 in whichembodiments of the microstrip circulator formed on the co-fired tile canbe an integral component.

FIG. 13 is a schematic diagram of one example of a mobile device 800.The mobile device 800 includes a baseband system 801, a transceiver 802,a front end system 803, antennas 804, a power management system 805, amemory 806, a user interface 807, and a battery 808 and can interactwith the base stations including embodiments of the microstripcirculators disclosed herein.

The mobile device 800 can be used communicate using a wide variety ofcommunications technologies, including, but not limited to, 2G, 3G, 4G(including LTE, LTE-Advanced, and LTE-Advanced Pro), 5G NR, WLAN (forinstance, Wi-Fi), WPAN (for instance, Bluetooth and ZigBee), and/or GPStechnologies.

The transceiver 802 generates RF signals for transmission and processesincoming RF signals received from the antennas 804. It will beunderstood that various functionalities associated with the transmissionand receiving of RF signals can be achieved by one or more componentsthat are collectively represented in FIG. 13 as the transceiver 802. Inone example, separate components (for instance, separate circuits ordies) can be provided for handling certain types of RF signals.

In certain implementations, the mobile device 800 supports carrieraggregation, thereby providing flexibility to increase peak data rates.Carrier aggregation can be used for both Frequency Division Duplexing(FDD) and Time Division Duplexing (TDD), and may be used to aggregate aplurality of carriers or channels. Carrier aggregation includescontiguous aggregation, in which contiguous carriers within the sameoperating frequency band are aggregated. Carrier aggregation can also benon-contiguous, and can include carriers separated in frequency within acommon band or in different bands.

The antennas 804 can include antennas used for a wide variety of typesof communications. For example, the antennas 804 can include antennasassociated transmitting and/or receiving signals associated with a widevariety of frequencies and communications standards.

In certain implementations, the antennas 804 support MIMO communicationsand/or switched diversity communications. For example, MIMOcommunications use multiple antennas for communicating multiple datastreams over a single radio frequency channel. MIMO communicationsbenefit from higher signal to noise ratio, improved coding, and/orreduced signal interference due to spatial multiplexing differences ofthe radio environment. Switched diversity refers to communications inwhich a particular antenna is selected for operation at a particulartime. For example, a switch can be used to select a particular antennafrom a group of antennas based on a variety of factors, such as anobserved bit error rate and/or a signal strength indicator.

FIG. 14 is a schematic diagram of a power amplifier system 840 accordingto one embodiment. The illustrated power amplifier system 840 includes abaseband processor 821, a transmitter 822, a power amplifier (PA) 823, adirectional coupler 824, a bandpass filter 825, an antenna 826, a PAbias control circuit 827, and a PA supply control circuit 828. Theillustrated transmitter 822 includes an I/Q modulator 837, a mixer 838,and an analog-to-digital converter (ADC) 839. In certainimplementations, the transmitter 822 is included in a transceiver suchthat both transmit and receive functionality is provided. Embodiments ofthe disclosed microstrip circulators/isolators and SIWcirculators/isolators can be incorporated into the power amplifiersystem.

Methodology

Disclosed herein are embodiments of a process for making microstripcirculators/isolators and SIW circulators/isolators. FIG. 15 disclosesan embodiment of a process 300 that can be used.

Returning to FIG. 15, at step 302, a ferrite disc or cylinder can beformed from a magnetic ceramic material by any suitable conventionalprocess known in the art for making such elements, i.e., ferrites of thetypes used in high frequency electronic components. Similarly, at step304, a substrate can be formed from a dielectric material by anysuitable conventional process. In some embodiments, the ferrite disc canbe sintered by firing it in a kiln. Some examples of materials andfiring temperatures are set forth below, following this process flowdescription. However, persons skilled in the art to which the inventionrelates understand that the materials and processes by which magneticceramic and dielectric ceramic elements of this type are made are wellknown in the art. Therefore, suitable materials and temperatures are notlisted exhaustively. All such suitable materials and process for makingsuch rods, cylinders and similar elements of this type are intended tobe within the scope of the invention.

At step 306, the disc can be combined into the dielectric substrate withthe aperture. For example, the outside surface of the disc can bemachined to ensure it is of an outside diameter (OD) that is less thanthe inside diameter (ID) of the substrate aperture. In some embodiments,the OD is slightly smaller than the ID to enable the disc to be insertedinto the substrate.

In some embodiments, the pre-fired disc can be received in an unfired or“green” substrate to form the composite assembly 100 shown in FIG. 4.

At step 308, the disc and substrate can be co-fired. That is, compositeassembly 100 is fired. The co-firing temperature can be lower than thetemperature at which disc was fired, to ensure that the physical andelectrical properties of the disc remain unchanged. Importantly,co-firing causes the substrate to shrink around the disc, therebysecuring them together. Afterwards, the outside surface of the compositeassembly 100 can then be machined to ensure it is of a specified orotherwise predetermined OD. Further, this step can be used to metalizeand/or magnetize the composite assembly 100 if the ferrite disc has notpreviously been magnetized.

Steps 310 and 312 show optional steps that can be taken after theco-firing of the composite assembly 100. For example, additionalcomponents can be added 310 onto the substrate, such as circuitry (e.g.,metalized circuitry), to form final electronic components. Further, insome embodiments the composite assembly 100 can be sliced 312, orotherwise partitioned, to form a number of discrete assemblies. In someembodiments, both these optional steps can be performed and theparticular order is not limiting. In some embodiments, only one of theoptional steps can be taken. In some embodiments, neither of theoptional steps can be taken.

Accordingly, composite assemblies 100 can be used in manufacturing highfrequency electronic components in the same manner asconventionally-produced assemblies of this type. However, the method ofthe present invention is more economical than conventional methods, asthe invention does not involve the use of adhesives.

EXAMPLES

FIG. 16 illustrates an example embodiment of a circulator as discussedherein. Thick film silver can be printed as the circuit. As per standardcirculator applications, the circulator includes Port 1, Port 2, andPort 3. One of these ports can be terminated to form an isolator.

FIGS. 17A-20B illustrate the scattering parameter measurements(S-parameter measurements), in particular the return loss on a standardgraph and a Smith Chart.

FIG. 17A illustrates return loss at Port 1 in dB (level of power lossdue to reflected signal at the input port of the circulator). FIG. 17Billustrates impedance measured at Port 1 (displayed on a Smith Chart).FIG. 18A illustrates a return loss at Port 2 in dB (level of power lossdue to reflected signal at the output port of the circulator). FIG. 18Billustrates impedance measured at Port 2 (displayed on a Smith Chart).FIG. 19A illustrates insertion loss of Port 1-2 (level of power loss dueto transmission from Port 1 to Port 2). FIG. 19B illustrates isolationof Port 2-1 (level of power loss due to transmission from Port 2 to Port1). FIG. 20A illustrates return loss at Port 3 in dB (level of powerloss due to reflected signal at the input port of the circulator). FIG.20B illustrates impedance measured at Port 3 (displayed on a SmithChart). The low forward transmission loss (e.g., insertion loss) andhigh reverse transmission loss (e.g., isolation) are advantageousparameters of the circulators operation. The low forward transmissionloss (e.g., insertion loss) improves the output efficiency of the poweramplifier. High reverse transmission loss (e.g., isolation) is anadvantageous parameter of circulator operation because of the improvedtransmit to receive isolation.

From the foregoing description, it will be appreciated that inventiveproducts and approaches for composite microstrip and SIWcirculators/isolators are disclosed. While several components,techniques and aspects have been described with a certain degree ofparticularity, it is manifest that many changes can be made in thespecific designs, constructions and methodology herein above describedwithout departing from the spirit and scope of this disclosure.

Certain features that are described in this disclosure in the context ofseparate implementations can also be implemented in combination in asingle implementation. Conversely, various features that are describedin the context of a single implementation can also be implemented inmultiple implementations separately or in any suitable subcombination.Moreover, although features may be described above as acting in certaincombinations, one or more features from a claimed combination can, insome cases, be excised from the combination, and the combination may beclaimed as any subcombination or variation of any subcombination.

Moreover, while methods may be depicted in the drawings or described inthe specification in a particular order, such methods need not beperformed in the particular order shown or in sequential order, and thatall methods need not be performed, to achieve desirable results. Othermethods that are not depicted or described can be incorporated in theexample methods and processes. For example, one or more additionalmethods can be performed before, after, simultaneously, or between anyof the described methods. Further, the methods may be rearranged orreordered in other implementations. Also, the separation of varioussystem components in the implementations described above should not beunderstood as requiring such separation in all implementations, and itshould be understood that the described components and systems cangenerally be integrated together in a single product or packaged intomultiple products. Additionally, other implementations are within thescope of this disclosure.

Conditional language, such as “can,” “could,” “might,” or “may,” unlessspecifically stated otherwise, or otherwise understood within thecontext as used, is generally intended to convey that certainembodiments include or do not include, certain features, elements,and/or steps. Thus, such conditional language is not generally intendedto imply that features, elements, and/or steps are in any way requiredfor one or more embodiments.

Conjunctive language such as the phrase “at least one of X, Y, and Z,”unless specifically stated otherwise, is otherwise understood with thecontext as used in general to convey that an item, term, etc. may beeither X, Y, or Z. Thus, such conjunctive language is not generallyintended to imply that certain embodiments require the presence of atleast one of X, at least one of Y, and at least one of Z.

Language of degree used herein, such as the terms “approximately,”“about,” “generally,” and “substantially” as used herein represent avalue, amount, or characteristic close to the stated value, amount, orcharacteristic that still performs a desired function or achieves adesired result. For example, the terms “approximately”, “about”,“generally,” and “substantially” may refer to an amount that is withinless than or equal to 10% of, within less than or equal to 5% of, withinless than or equal to 1% of, within less than or equal to 0.1% of, andwithin less than or equal to 0.01% of the stated amount. If the statedamount is 0 (e.g., none, having no), the above recited ranges can bespecific ranges, and not within a particular % of the value. Forexample, within less than or equal to 10 wt./vol. % of, within less thanor equal to 5 wt./vol. % of, within less than or equal to 1 wt./vol. %of, within less than or equal to 0.1 wt./vol. % of, and within less thanor equal to 0.01 wt./vol. % of the stated amount.

Some embodiments have been described in connection with the accompanyingdrawings. The figures are drawn to scale, but such scale should not belimiting, since dimensions and proportions other than what are shown arecontemplated and are within the scope of the disclosed inventions.Distances, angles, etc. are merely illustrative and do not necessarilybear an exact relationship to actual dimensions and layout of thedevices illustrated. Components can be added, removed, and/orrearranged. Further, the disclosure herein of any particular feature,aspect, method, property, characteristic, quality, attribute, element,or the like in connection with various embodiments can be used in allother embodiments set forth herein. Additionally, it will be recognizedthat any methods described herein may be practiced using any devicesuitable for performing the recited steps.

While a number of embodiments and variations thereof have been describedin detail, other modifications and methods of using the same will beapparent to those of skill in the art. Accordingly, it should beunderstood that various applications, modifications, materials, andsubstitutions can be made of equivalents without departing from theunique and inventive disclosure herein or the scope of the claims.

What is claimed is:
 1. A method of forming a co-fired integratedmicrostrip or substrate integrated waveguide circulator, the methodcomprising: preparing a ferrite disc; preparing a dielectric substrate,the dielectric substrate having an aperture; translating the ferritedisc into the aperture in the dielectric substrate to form a compositestructure; co-firing the composite structure to shrink the dielectricsubstrate around the ferrite disc; and metallizing the co-firedcomposite structure.
 2. The method of claim 1 wherein the ferrite discis an yttrium iron garnet disc.
 3. The method of claim 1 wherein theco-firing is at a temperature of at least 1000° C.
 4. The method ofclaim 1 further including adding additional radio frequency componentsonto the dielectric substrate.
 5. The method of claim 1 furtherincluding slicing the composite structure to a particular thickness,wherein each slice contains both a portion of the ferrite disc and aportion of the dielectric substrate or waveguide.
 6. The method of claim1 further including contacting a magnetic disc onto the compositestructure to form a microstrip or substrate integrated waveguidecirculator.
 7. The method of claim 1 wherein no adhesive is used.
 8. Themethod of claim 1 further including applying a coupler, switch, and loadto the dielectric substrate.
 9. The method of claim 8 further comprisingcoupling the coupler to a transmit power amplifier and coupling theswitch to a receive low noise amplifier.
 10. The method of claim 8further comprising printing a microstrip filter on the dielectricsubstrate.
 11. A method of forming a radio frequency antenna system, themethod comprising: preparing a ferrite disc; preparing a dielectricsubstrate, the dielectric substrate having an aperture; translating theferrite disc into the aperture in the dielectric substrate to form acomposite structure; co-firing the composite structure to shrink thedielectric substrate around the ferrite disc; metallizing the co-firedcomposite structure; printing a coupler on the dielectric substrate; andcoupling a transmit power amplifier to the coupler.
 12. The method ofclaim 11 wherein the ferrite disc is an yttrium iron garnet disc. 13.The method of claim 11 wherein the co-firing is at a temperature of atleast 1000° C.
 14. The method of claim 11 further including addingadditional radio frequency components onto the dielectric substrate. 15.The method of claim 11 further including slicing the composite structureto a particular thickness, wherein each slice contains both a portion ofthe ferrite disc and a portion of the dielectric substrate or waveguide.16. The method of claim 11 further including contacting a magnetic disconto the composite structure to form a microstrip or substrateintegrated waveguide circulator.
 17. The method of claim 11 wherein noadhesive is used.
 18. The method of claim 11 further including applyinga switch and load to the dielectric substrate.
 19. The method of claim11 further comprising coupling the switch to a receive low noiseamplifier.
 20. The method of claim 11 further comprising printing amicrostrip filter on the dielectric substrate.